Bosch Premium Class Platinum+4 Spark Plug contains the most platinum in the Bosch Platinum Plug Series and has a unique firing technology that combines the advantages of surface air gap technology and 4 yttrium enhanced ground electrodes.

Specifications:

14 mm thread size

19 mm reach

20.6 mm hex size

Platinum plug

Gasket seat style

Interference suppression resistor

Surface air gap plug

Heat fused platinum center electrode

4 ground electrodes

Heat range 8

Features:

Reduces the voltage necessary to jump the gap as well as quenching

Provides multiple radial spark paths and surface air gap design that creates optimal exposure of the air/fuel mixture to the enhanced ignition spark

"These spark plugs are impossible to screw in. The thread is good and can go into the engine but the bolt you have to use to screw it in has to be paper thin since the overal spark plug is too fat."posted by: Car person on February 9, 2011